Frostpunk isn't an endless city builder: the campaign lasts about 45 days (which took me roughly 12 hours), culminating in an event that will put your fragile city and citizenry to the test in unthinkable conditions. It does feel a bit strange when the game ends. I'm used to open-ended city builders that let me play as long as I want, and I certainly would have enjoyed to opportunity to continue to tinker with my city after the final curtain, so that's a bit disappointing. There's some replayability here: choosing different laws the next time, trying to avoid the mistakes of the last campaign, though the major events and discoveries will be the same each time. One full game is enough to unlock nearly everything in the tech trees, so a replay won't be a wholly different or surprising experience.